[ardour-users] Re: [ardour-dev] Strange Issue WIth Automation in ardour-0.9_beta11

[Paul Davis]

>I recently ran into some problems whenever automation is enabled on any 
>track with ardour-0.9_beta11. These were usually indicated as disktream 
>errors in the ardour log window, and when checking the log generated 
>from jackd and ardour (this is run as an sudo session on a script in my 
>home directory), there were playback underruns shown that seemed to 
>correlate with the log window errors.  A sample of these errors is 
>copied below:
>
>---------------------------------------------------------------------
>DiskStream Vocals:0: playback underrun (called with 8193 samples but 
>only 5933 vailable; other half: 0) [speed=8]
>---------------------------------------------------------------------

Please notice the "[speed=8]" line. You were apparently
fast-forwarding when this happened. An 8-fold speed up is quite a lot,
especially if you have only 7200 RPM disks (or worse). If you weren't
ffwd-ing, we have some other bug to solve, because ardour thinks you were.

>Another, possibly unrelated, dilemma is an issue I have been 
>encountering when running latencies (with or without automation) at or 
>below 3 ms latency (i.e., p=256, n=2 @ 48KHz sampling rate) when running 
>a 2.4 kernel. In this case, the ardour log window displays a bizarre 
>error message saying something about a MIDI memory pool error and to 
>please compile with larger size.  When I run a 2.6 kernel, this error 
>does not seem to occur. 

i am sorry to say that this is a long standing problem that we have
never tracked down. i hope we can solve it before the release of 1.0.
please make sure its registered with mantis (ardour.org/mantis)

>sessions), however, the disk stream errors persist whenever automation 
>is enabled and my system latency is set any lower than 11ms 
>(p=1024,n=2 at 48KHz).
>
>My current workaround is to run the gentoo development kernel 2.6.3-r1, 
>and use low latencies as low as 3 ms for recording or non-automated 
>mixdowns, and a setting of 11ms latency or greater if I am mixing down 
>with automnation.

how many tracks are you using? a PIII-450 is not a particularly speed
machine, and it *is* possible that automation is bogging you
down. however, the problems you mentioned above are not related to
automation in any direct sense.